package com.lwq.lwqmicoservice.common.util;

import org.springframework.beans.BeanWrapper;
import org.springframework.beans.BeanWrapperImpl;

import java.beans.FeatureDescriptor;
import java.util.Arrays;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.function.Function;
import java.util.function.Predicate;
import java.util.stream.Stream;

/**
 * Description:
 * Author: LiuWenQing
 * Datetime: 2021/6/11
 */
public class BeanAssistant {

    public static String[] getNullPropertyNames( Object source, String... ignoreProperties )
    {
        final BeanWrapper wrappedSource = new BeanWrapperImpl(source);
        return Stream.of(wrappedSource.getPropertyDescriptors())
                .map(FeatureDescriptor::getName)
                .filter(propertyName -> wrappedSource.getPropertyValue(propertyName) == null || Arrays.asList(ignoreProperties).contains(propertyName))
                .toArray(String[]::new);
    }


    public static <T> Predicate<T> distinctByKey(Function<? super T, Object> keyExtractor)
    {
        Map<Object, Boolean> seen = new ConcurrentHashMap<>();
        return t -> seen.putIfAbsent(keyExtractor.apply(t), Boolean.TRUE) == null;
    }
}
